This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Fire blight is a devastating plant disease that is caused by Erwinia amylovora, a Gram-negative bacterium. The disease affects more than a hundred rosaceous plant species, including the commercially important apple and pear trees. Pantocin A is a novel peptide-based antibiotic produced by Pantoea agglomerans, another Gram-negative bacterium, to inhibit the growth of E. amylovora. This project attempts to utilize both structural biology and biochemistry tools to elucidate the biosynthesis of pantocin A.